Investigation of surface properties of Ru-based oxide electrodes containing Ti, Ce and Nb

• Published in: Electrochimica acta 2003-06, Vol.48 (13), p.1885-1891
• Main Authors: Santana, Mário H.P., Da Silva, Leonardo M., De Faria, Luiz A.
• Format: Article
• Language: English
• Subjects: Cerium oxide; Chemistry; Electrochemistry; Electrode stability; Electrodes: preparations and properties; Exact sciences and technology; General and physical chemistry; Niobium oxide; Other electrodes; Oxide electrodes; Roughness factor
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/S0013-4686(03)00262-7

Mixed oxide electrodes with nominal composition Ti/[Ru (0.3)Ti (0.6)Ce (0.1− x) ]O 2[Nb 2O 5] ( x) , (0≤ x≤0.1) were prepared through a process of thermal decomposition (450 °C) of chloride precursor mixture solutions. Composition effects on the surface properties were investigated and the oxide electrodes were characterized in acid solution: ex situ by XRD and in situ by open circuit potential measurements ( E oc), cyclic voltammetry (CV), the double-layer capacitance (CV and electrochemical impedance spectroscopy techniques) and roughness factor (CV). Except the E oc, all parameters varied with the electrode composition. It was shown that the presence of CeO 2 increases the electrochemical active area, but it makes the coating less stable when submitted to continuous potential cycles because of cathodic dissolution of this oxide. By adding Nb 2O 5 this instability can be lowered. The maximum activity (voltammetric charge) was observed with the [Ru (0.3)Ti (0.6)Ce (0.07)]O 2[Nb 2O 5] (0.03) composition.